#!/bin/bash

PRJ_PATH=`pwd`
PRJ_NAME=`basename ${PRJ_PATH}`

BOARD=imx6ull

DRV_PATH=${PRJ_PATH}/driver
TAR_PATH=${PRJ_PATH}/../tarball

# rootfs should be buildroot/yocto or stretch/buster/bullseye for debian system
ROOTFS=buildroot

ROOTFS_DIR=rootfs_${ROOTFS}
ARCH=arm

# rootfs configuration
DEF_USER=lingyun
DEF_PASSWD=12345
DEF_HOSTNAME=${BOARD}

APT_CONF=extra_apps.json

set -u
set -e

trap 'exit_handler' EXIT
function exit_handler()
{
    rm -f  ${ROOTFS_DIR}/usr/bin/qemu-arm-static
    umount ${ROOTFS_DIR}/{sys,proc,dev/pts,dev} 2>/dev/null || true
}

STAGE=0
function msg_banner()
{
    STAGE=`expr $STAGE + 1`

    echo ""
    echo "+---------------------------------------------+"
    printf " Stage $STAGE: $1\n"
    echo "+---------------------------------------------+"
    echo ""
}

function do_unpack()
{
    if [ -d ${ROOTFS_DIR} ] ; then
        printf "\n\n -- ${ROOTFS_DIR} fetched already, skip it -- \n\n"
        return;
    fi

    if [ -s ${TAR_PATH}/${ROOTFS_DIR}.tar.bz2 ]  ; then
        printf "\n\n -- decompress ${ROOTFS_DIR}.tar.bz2 -- \n\n"
        mkdir -p ${ROOTFS_DIR}
        tar -xjf ${TAR_PATH}/${ROOTFS_DIR}.tar.bz2 -C ${ROOTFS_DIR}
    fi

    return;
}


# debootstrap fetch debian rootfs
function do_fetch()
{
    msg_banner " ${ROOTFS_DIR} do fetch "

    # try to decompress packet first.
    do_unpack

    if [ $ROOTFS == "buildroot" -o $ROOTFS == "yocto" ] ; then
        if [ ! -d ${ROOTFS_DIR} ] ; then
            echo " ERROR: miss rootfs ${ROOTFS}, exit now. "
            echo ""
            exit;
        else
            return 0;
        fi
    fi

    export DEBIAN_FRONTEND=noninteractive
    export DEBCONF_NONINTERACTIVE_SEEN=true
    export LC_ALL=C
    export LANGUAGE=C
    export LANG=C

    printf "\n\n -- debootstrap fetch start --\n\n"
    debootstrap --arch=${ARCH} --foreign ${ROOTFS} ${ROOTFS_DIR} http://ftp.cn.debian.org/debian/

    chroot ${ROOTFS_DIR} debootstrap/debootstrap --second-stage
    printf "\n\n -- debootstrap config start --\n\n"

    chroot ${ROOTFS_DIR} dpkg --configure -a
    printf "\n\n -- debootstrap fetch done -- \n\n"

    # Clear the MD5 value to install extra apps
    sed -i -e "s|.*md5val.*|\t\"md5val\":\"MD5_Auto_Generate_Here\"|g" $APT_CONF
}

# Install extra apps defined in extra_apps.conf
function do_apt()
{
    export DEBIAN_FRONTEND=noninteractive
    export DEBCONF_NONINTERACTIVE_SEEN=true
    export LC_ALL=C
    export LANGUAGE=C
    export LANG=C

    msg_banner " debootstrap apt install "

    if [ -f $APT_CONF ] ; then
        extra_apps=$(eval jq -r .extra_apps[] $APT_CONF )
        md5_file=$(eval jq -r .md5val extra_apps.json)
        md5_calc=$(eval echo $extra_apps | md5sum | awk '{print $1}')


        if [ $md5_file == $md5_calc ] ; then
            printf "\n\n -- debootstrap apt install already, skip it! --\n\n"
        else
            printf "\n\n -- debootstrap apt install start --\n\n"

            cp -f /usr/bin/qemu-arm-static ${ROOTFS_DIR}/usr/bin/
            mount -o bind /proc ${ROOTFS_DIR}/proc
            mount -o bind /dev ${ROOTFS_DIR}/dev
            mount -o bind /dev/pts ${ROOTFS_DIR}/dev/pts
            mount -o bind /sys ${ROOTFS_DIR}/sys

            chroot ${ROOTFS_DIR} apt update
            chroot ${ROOTFS_DIR} apt install -y ${extra_apps}

            umount ${ROOTFS_DIR}/{sys,proc,dev/pts,dev}

            sed -i -e "s|.*md5val.*|\t\"md5val\":\"$md5_calc\"|g" $APT_CONF
            printf "\n\n -- debootstrap apt install done --\n\n"

            # modify root password
            chroot ${ROOTFS_DIR} sh -c "echo root:${DEF_PASSWD} | chpasswd"

            # add extra user account
            set +e
            grep "$DEF_USER" ${ROOTFS_DIR}/etc/passwd > /dev/null 2>&1
            if [ $? != 0 ] ; then
                printf "\n\n -- setup default user account --\n\n"
                chroot ${ROOTFS_DIR} sh -c "useradd -m -s /bin/bash ${DEF_USER}"
                chroot ${ROOTFS_DIR} sh -c "echo ${DEF_USER}:${DEF_PASSWD} | chpasswd"
                chroot ${ROOTFS_DIR} sh -c "usermod -G video,audio,sudo avnet"

                echo "${DEF_USER}    ALL=(ALL:ALL) NOPASSWD:ALL" >> ${ROOTFS_DIR}/etc/sudoers
            fi
            set -e
        fi
    fi
}

function do_modules()
{
    if [ ! -d ${DRV_PATH}/lib/modules ] ; then
        return ;
    fi

    msg_banner " install kernel modules"

    rm -rf ${ROOTFS_DIR}/lib/modules/
    cp -af ${DRV_PATH}/lib/modules  ${ROOTFS_DIR}/lib/

    if [ ! -d ${ROOTFS_DIR}/lib/firmware -a -s firmware.tar.bz2 ] ; then
        tar -xjf firmware.tar.bz2 -C ${ROOTFS_DIR}/lib/
    fi

    printf "\n\n -- install kernel modules done --\n\n"
}

function do_modify()
{
    msg_banner " modify rootfs environment"

    set +e

    # update hostnmae and issue
    echo "GNU/Linux $ROOTFS \n \l, default password '$DEF_PASSWD'." > ${ROOTFS_DIR}/etc/issue
    echo $DEF_HOSTNAME > ${ROOTFS_DIR}/etc/hostname
    grep "$BOARD" ${ROOTFS_DIR}/etc/hosts > /dev/null 2>&1
    if [ $? != 0 ] ; then
       echo "127.0.0.1       ${BOARD}" >> ${ROOTFS_DIR}/etc/hosts
    fi

    # update dns server
    echo "nameserver 114.114.114.114" > ${ROOTFS_DIR}/etc/resolv.conf
    echo "nameserver 223.5.5.5" >> ${ROOTFS_DIR}/etc/resolv.conf

    # add ls alias for display with color
    grep "color=auto" ${ROOTFS_DIR}/etc/profile > /dev/null 2>&1
    if [ $? != 0 ] ; then
       echo "alias ls='ls --color=auto'" >> ${ROOTFS_DIR}/etc/profile
    fi

    # permit root ssh login
    sed -i "s|^#PermitRootLogin.*|PermitRootLogin yes|g" ${ROOTFS_DIR}/etc/ssh/sshd_config
    sed -i "s|^#PasswordAuthentication.*|PasswordAuthentication yes|g" ${ROOTFS_DIR}/etc/ssh/sshd_config

    set -e

    printf "\n\n -- modify rootfs done --\n\n"
}

function do_pack()
{
    if [ -f ${ROOTFS_DIR}.tar.bz2 ] ; then
       msg_banner " rootfs already generate, skip it"
       return ;
   else
       msg_banner " generate rootfs packet "
    fi

    cd ${ROOTFS_DIR}

    tar -cjf ../${ROOTFS_DIR}.tar.bz2 *

    cd ${PRJ_PATH}

    printf "\n\n -- generate rootfs packet done --\n\n"
}

function do_distclean()
{
    printf "\n\n -- do distclean in $PRJ_NAME --\n\n"

    rm -rf driver
    rm -rf $ROOTFS_DIR

    exit;
}

function do_rootfs()
{
    do_fetch

    echo "do rootfs continue "

    # debian rootfs need apt install packet
    if [ $ROOTFS != "buildroot" -a $ROOTFS != "yocto"  ]  ;then
        do_apt
    fi

    do_modules
    do_modify
    do_pack
}

function do_root()
{
    echo ""
    if [[ $1 == "yes" ]] && [ `id -u` != 0 ] ; then
        echo "ERROR: This action must run as root!"
        echo ""
        exit;
    elif [[ $1 != "yes" ]] && [ `id -u` == 0 ] ; then
        echo "ERROR: This action cannot run as root!"
        echo ""
        exit;
    fi
}

function do_usage()
{
    echo ""
    echo "Usage:"
    echo "   $0 [-b] [-c] [-h]"
    echo "       -b: download and build $PRJ_NAME"
    echo "       -c: clean all the source code"
    echo "       -h: show this help message"
    echo ""
    echo " WARNNING: This shell script must run as sudo"
    echo ""
    exit;
}

while getopts "bch" OPTNAME
do
    case "${OPTNAME}" in
        "b")
            break;
            ;;

        "c")
            do_root "yes"
            do_distclean
            ;;

        "*")
            do_usage
            ;;
    esac
done

do_root "yes"
do_rootfs